1. Field of the Invention:
This invention relates to motorcycles and more particularly to two-wheeled motorcycles of the type including a shell structure which, forming at least a portion of the vehicle frame, is designed to cover the propelling power unit of the vehicle.
2. Description of the Prior Art:
Generally, with two-wheeled motorcycles, many attempts have previously been made to reduce the vehicle weight as any slight difference in vehicle weight has a great influence upon the various vehicle performances such as acceleration and maneuverability. However, with the conventional motorcycle construction, including a vehicle frame formed of steel tubing or steel sheet, so as to exhibit practically sufficient strength by itself and a power unit mounted on such vehicle frame, it may safely be said that reduction in vehicle weight has already nearly reached its limit.